Fluid actuated piston distributing valve with fluid actuated piston pilot valve for expansible chamber motors



Oct. 19, 1948. E. c. sEwARD ETAL. 2,451,983

FLUID ACTUTED PISTON DISTRIBUTING VALVE WITH FLUID ACTUATED PISTON PILOT VALVE FOR EXPANSIBLE CHAMBER MOTORS 2 Sheets-Sheet 1 Filed April 9, 1945 Oct. 19, 1948. E, C, SEWARD ET AL 2,451,983

FLUID AGTUATED PIsToN DISTRIBUTING VALVE WITH FLUID ACTUATED PISTON PILOT VALVE FOR EXPANSIBLE CHAMBER MOTORS Filed April 9, 1945 2 Sheets-Sheet 2 @4A/,e Macarr- Patented oct. .19, 194s FLUID ACTUATED PISTON DISTRIBUTING VALVE WITH FLUID ACTUATED PISTON PILOT VALVE FOR EXPANSDSLE CHAM- BER,` MOTORS Edgar o. Seward, Arnngtbn, va., ami Frank Waloutt, Queens Village, N. Y.

Application April 9, 1945, Serial No. 587,390

l 3 Claima' This invention relates to a hydr'aulic valve which is simple in construction and operation and which is designed to replace complicated and cumbersome mechanical drives with positive, hydraulic action. The invention is particularly adaptable in situations requiring continuous motion, whether reciprocating, oscillating or rotary. It is suitable for use in conjunction with pumps and continuous, reciprocating, double acting, cylinder motions on a closed circuit, in which it may operate one or more cylinders of varied length and diameter in parallel, or 'lt may operate cylinders in series. The invention is particularly adaptable for operating shaker screens, stocker devices, shapers, presses, washing machines and thelike.

Another object of the invention ls the provision of a reversible valve, in which the valve may be reversed automaticallyat any desired pressure within the limits of its range.

A further object is the provision of a hydraulic valve which reduces to aminimum the possibility of damage to associated devices because, by reason of its construction, once the predetermined pressure is reached, the valve automatically reverses and then continues in operation until the predetermined pressure is again reached and the resistance of the fluid circuit builds up again. The motion is continuous.

Another object of the invention is the provision of such a valve having only a few simple, moving parts. y

Still a further object is the provision of a dual piston, reversible hydraulic valve in which one of the pistons must complete its stroke before the other begins to move, providing surety of control and safety in operation, the reversing action of the valve being incomplete until both pistons have completed a stroke.

For a morecomplete understanding of the invention'reference isl made to the accompanying drawings and description which illustrate and exemplify a preferred embodiment of the invention, but which are not intended to limit the invention to the construction shown.

Figure 1 represents a central, longitudinal vertical section through the valve, showing the pistons thereofA at the beginning or end of a cycle of operation.

Figure 2 is a view'similar to that of Figure 1, showing the pistons in position after having completed one phase, or one-half cycle of operation.

Figure 3 is an end view of the valve shown in Figure l with an end plate removed, showing the cylinders and delineating the passages for the hydraulic fluid.

Figure 4 is a perspective view of the upper piston.

Figure 5 is a perspective view of the lower piston. i

The valve embodies a casing I0, having spaced longitudinal cylinders II, I2, which will be called primary and 'secondary cylinders, respectively, merely for convenience of description. The casing is closed at each end by plates I3 which are securely held in place by bolts I4. Each cylinder I I, I2, is provided with a primary piston I Ia, and a secondary piston, I 2a, respectively. The casing has an inlet port I5 on one side leading to a suitable pump and ports I6, I6a leading to or from a working cylinder, according to the cycle of operation. Each cylinder is directly connected to a sump or reservoir (not shown) by means -of passages and ports hereinafter described.

The cylinders II and I2 are interconnected by a series of ports and passages which delineate the working circuits of the valve. The left hand end of cylinder II, or its pressure chamber in the phase of operation as shown in Figure 1, is connected to a cylinder I2 by means of passage I1. The right hand end of cylinder II is connected to cylinder I2 by means of passage I8. These cylinders are also connected by means of port I9, passage I9a and port 20, passage 20a, whose functions will be more fully described. A centrally located passage 9 connects cylinders I I and I2 at one side of thebore 30. The diameter of each piston is yreduced at 2| at each end so as to prevent the piston from closing off the cylinder and to provide a chamber 22a, 22h, 22c, 22d, in the cylinders adjacent the passages I l, I8, I9a, 20a, respectively. The piston Ila in theupper cylinder, as best shown in Figure 4, has a pair of longitudinally spaced, elongated slots 23, 24, milled or otherwise cut through its body, substantially K along the line of its longitudinal axis and arranged substantially equidistant oneach side of a line erected perpendicularly at a point midway between its ends. The surface of the piston is transversely reduced or notched as at 25, 25a, and a slight at bearing surface 26 is ground or otherwise formed between the said notches so as to reduce said at surface slightly below the cir-v cumference of the piston. Similar notches and a fiat are formed at the diametrically opposite sidev of this piston.

The piston I2a, in Figure 5, is likewise notched at 21, 21a and has a slightly reduced fiat bearing surface 28 between said notches. Opposite these openings 2l, Ilawhich are shown as substantially rectangular in side elevation. l f As shown in Figure l, the casing Iii has a boss Vlla extending upwardly from one face. .The boss andcasing are provided with a vertical bore 30 which extends through each cylinder. Seated in this bore and suitably keyed therein to prevent rotation are two pins 3i, 32. the pin 3i being .formed at its lower end with a chisel point'iia to seat in one or the other of the notches'25, 25a, according to the phase of operation. This pin is This movement ends the second phase of operation and also accomplishes several functions.

Iiirst, the upward movement of the pin 82 as I it rides over iiat 2l has locked piston liaagainst maintained in yieldable relation to piston IIa by Y means of spring $8, the pressure of which is controlled by adjusting screw Il. or other suitable means.

The pin 22, which slides freely in the bore l2 is provided with a chisel point 32a, 32h at its upper and lower end, respectively, and normally rests with the chisel point 32h in the notch 21 or 21a of piston I2, according to the operation, which will now be-explained.

'The operation of the valve is as follows: Assuming the valve to be a working part of a hydraulic circuit in which a pump (not shown) delivers working iiuid under pressure to the inlet Il, as shown in Figure 1, with the pin 2i adjusted for a predetermined working pressure by means of adjusting screw u. in the first phase of operation the ii'uid under pressure ilows from the inlet port I 5, through the slot 29a in piston Ila into passage I1 and up to chamber 22a in left hand end of cylinder II`. Fluid pressure is simultaneously maintained through passage 9, port l5. slot 2l, port 20 and passage 20a, with the right hand end of cylinder I2, holding piston I2a against left hand end oi' cylinder I2. When the pressure in chamber 22a, under the operation of the pump (not shown), builds up to the predetermined point where it ls sufficient lto overcome the resistance of the spring 33, the piston Ha will be kickedover to the right hand end of cylinder Il'. As this takes place. the chisel point la of the pin 3| will be forced out of notch 25a bv the working pressure of the fluid against the piston and the chisel point will ride over the fiat surface 26 of piston Ila until it finds its seat in notch 25. This movement of the piston, as seen in Figure 2, shifted the slots'23, 24. so as to close port 38 and to open port 31. At the same time, the iluid in chamber 22o at the right hand end of kcylinder Ii was forced into passage I8, slot 29 and discharged' through outlet 38 (Figure-1) to a sump (not shown).

It is important to note that during the time the piston I Ia was moving to the right, the piston I2a was positively locked against movement by means of the pin l2, the point 32h of which was maintained seated in notch 21a by the flat surface 26a of the piston IIa. which was riding across the chisel point 32a. h

With the piston lia at the right hand end of the cylinder, (Flgure2) the direction of flow lof the fluid changes after entering through inlet I5 and ilows through passage 9, port 35 into slot 23, whence it passes through port I9, passage I9a to chamber 22h, until sufficient pressure i-s built up to overcome the resistance of pin 32, resting in notch 21a of the piston I2a. All chisel points and the corners of the notches in all pistons are rounded slightly so as to permit the pins to ride easily over them. When the pressure last referred to has overcome the resistance oiered by pin 32, the piston I2a is kicked over to the right.

movement, as the chisel point `22a becomes seated in notch 25a and remains there until the lower end 32h has passed over the surface 28 of the 'piston I2a and drops into notch 21. This movement of piston I2a to the right forces fluid from chamber 22d through passage 20a, ports 20, slot 22, port I] and passage 39a' for discharge to the sump. Second, the connection between ports II and Ita has been broken by the shifting of the connecting opening or slot 29a. The operation of the valve has now been reversed. The hydraulic iluid entering inlet port il now passes through slot 29 to lp'ort I8 and thence through passage I8 to chamber 22c where, when pressure against the end face of piston lia builds up to the predetermined point necessary to overcome the resistance of spring 33 and plunger 3i, the piston will kick over to the left. Thereupon the procedure heretofore outlined is initiated in reverse and in a, manner which will be understood by those skilled in the art, and pistons Ila and I2a will be moved, alternately, to the left. The valve will again have been reversed and a cycle of operation will have been completed.

It will thus be seen that the-operation of the valve is accomplished in four phases. The first phase is accomplished by the shifting of one (primary) piston from one end of the cylinder to the other, while the other (secondary) piston is lockedA (by said primary piston and pin) against movement. The second phase' begins vwhen the first (primary) piston has completed 1 its stroke and the other (secondary) piston moves to-the other end of the cylinder, while simultaneously locking the first (primary) piston against movement. When these two phases are accomplished, one-half cycle of operation of the valve isl completed. When the pistons return to the end of the cylinder where the cycle began, they complete two more phases, and thus one full cycle.

If, during the operation of the valve in a working circuit, the resistance builds up beyond the predetermined working pressure of the valve at the maximum limit, or if the pistons of the working cylinders (not shown) become locked in any part of their stroke,no damage will result. as the valve will automatically displace the working iluid by continuous rapid reversing,

While the pressure control medium has been shown as an adjustable screw and spring, the pressure control may be accomplished by other means as will be understood by those skilled in the art.

Other changes in the construction and design of the invention may be made, as will be well understood by those skilled in the art, without departing from the spirit of the invention as defined by the appended claim.

We claim as our invention:

l. A hydraulic reversing valve comprising a casing, a pair of bores in said casing, a piston in each of said bores and arranged to reciprocate therein, one of said pistons having a pair of longitudinally spaced elongated slots transversely provided therein and arranged to permit fluid ilow individually therethrough, the other of said pistons having a pair of spaced recesses provided on a portion of the surface thereof andv ond piston as said pistons reciprocate, to permit iirst bore with pressure outlets from said casing,

and a passage connecting a port in each ofl said bores with a pressure inlet in said casing, said latter ports in each bore being located centrally of the other ports therein.

2. A fluid pressure reversing valvecomprising f in combinationv a casing having a pair of cylinders, primary and secondary piston valves mounted for reciprocation in said cylinders, a uid pressure inlet connected to said primary and secondary cylinders, a pair of fluid pressure outlets in said secondary cylinder, said secondary piston having means for directing iuidirom said inlet to one or the other of said outlets, said means also serving to direct iluid from said inlet to either end of said primary cylinder depending upon the position of said secondary piston whereby said primary piston will be selectively reciprocated, said primary piston having means for directing iluid from said inlets to either end of said secondary cylinder depending upon the position of said primary piston whereby said secondary piston will be selectively reciprocated, an adjustably loaded detent engaging said primary piston and constructed and arranged to prevent reciprocation thereof by iluidpressure 3. A iiuid pressure reversing valve comprising in combination acasing having a pair of cylinders, primary and secondary piston -valves mounted for reciprocation in said cylinders, a iluid pressure inlet connected to said primary and secondary cylinders, a pair of iluid pressure A outlets in said secondary cylinder, said secondary piston having means for directing uid from said inlet to one or the other of said outlets, said means also serving to direct uid from said inlet to either end of said primary cylinder depending upon the position of said secondary-piston whereby said primary piston will be selectively reciprocated, said primary piston having means for directing iiuid from said inlet to either end of said secondary cylinder depending upon the position of said primary piston whereby said secondary piston will be selectively reciprocated, .means engaging said primary piston for preventing reciprocation thereof by uid pressure lin either end of said primary cylinder below a predetermined value, and means engaging said `primary and secondary pistons for preventing in either end of said primary cylinder below a predetermined value and a single slidably mounted interlocking detent engaging said primary and secondary pistons constructed andarranged to prevent movement of one piston during move- 4ment of the other piston whereby the operation movement of one piston diuing movement of the other piston whereby the operation of said secondary piston will be positively controlled by the operation of said primary piston in response to a predetermined pressure at either of said outlets. i

EDGAR C. SEWARD. `FRANK WALCUTI.

The following references are of record inthel Hill et al Dec'. 2, 1941 

